The present invention relates to a refrigeration and air conditioning system. In particular, the invention relates to a method and apparatus for saving energy in the operation of a large building air conditioning system.
In large, multi-story buildings air conditioning systems are designed to promote year-round cooling. This characteristic is essential to a cooling system designed for buildings in which the outer peripheral surfaces and areas are subject to wide temperature gradients whereas the inner portions remain relatively stable regardless of the ambient conditions. Such an air conditioning system must, in general, be operated for substantially the entire year to provide the necessary cooling and air circulation. During the mild and cold weather months of the year the system can be operated without the compressor where ambient conditions permit.
Various methods and apparatuses are disclosed in the art for minimizing the time that is necessary to run a compressor. See, for example, U.S. Pat. Nos. 2,718,766; 3,191,396; 3,242,689; 3,412,569; and 3,744,264.
When the system is run without the compressor, significant amounts of energy are saved because a compressor consumes large amounts of energy when it is operated. Therefore, to reduce the amount of energy consumed by the air conditioning system in a building, it is desirable that the time during which the compressor is operated be minimized.